Maintaining patient body temperature at an acceptable level is very important in many medical procedures. For example, if a patient's body temperature drops below the normal level during a surgery, the patient could possibly develop hypothermia, which can prolong or complicate the patent's recovery. If a patient is kept warm before, during and after surgeries, post-operative problems such as excessive bleeding, infection and etc. can be minimized.
To maintain a patient's body temperature, a variety of medical warming devices have been designed. Some of these medical warming devices require wires for transmitting temperature data and control signals. Some of these medical warming devices require manual control of heating elements. Some of these medical warming devices sense only the temperature of the heating elements rather than the accurate temperature of the patient's body. Fast heating response with temperature control at high accuracy is generally desired in a medical warming device. The above mentioned medical warming devices generally cannot satisfactorily achieve these purposes.
In medical procedures, another essential operational condition is that a medical warming device does not generate magnetic interference to other equipments. Conventional heating methods such as metal wire heating, metal coil heating and induction heating all induce magnetic field through operation and thus create magnetic interference to other equipments.